Support WhereRefBind log entries

[KirillOsenkov]

I've been using Fusion++ today, it's a great tool!

I noticed that it looks like it may not support all entries. Specifically if I run fuslogvw.exe and specify log all binds to disk, I may get files with this format: WhereRefBind!Host=(LocalMachine)!FileName=(Microsoft.Build.NuGetSdkResolver.dll).htm

These don't seem available in Fusion++.

To get a repro:

1. git clone https://github.com/dotnet/msbuild (assuming you cloned into C:\MSBuild), checkout main as of 2021-03-24 (e.g. dotnet/msbuild@bf0b0c5)
2. build -bl /p:CreateBootstrap=true
3. C:\msbuild\artifacts\bin\bootstrap\net472\MSBuild\Current\Bin\MSBuild.exe /r C:\temp\net472\net472.csproj where net472.csproj is any dotnet C# project. Note /r is important as the codepaths involve NuGet

Run step 3 under fuslogvw and Fusion++ and compare the results.

dotnet/msbuild#6289 is the issue we're investigating. Looks like we first load an assembly using Assembly.LoadFrom(), which loads it into the LoadFrom context, then we load the same .dll into the default load context, so we have two copies of the assembly loaded from two different codepaths, then we get the exception.

[awaescher]

Whoa, great spot. I will have a look at this soon.
Thanks for the feedback.

[awaescher]

Fusion++ checks if it was able to parse log entries by looking if the corresponding entry has a DisplayName.

This is okay for "ordinary" logs like this:

=== Zustandsinformationen vor Bindung ===
LOG: DisplayName = System.Xml.Linq, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
 (Fully-specified)
LOG: Appbase = file:///D:/Develop/GitHub/msbuild/artifacts/bin/bootstrap/net472/MSBuild/Current/Bin/
LOG: Ursprünglicher PrivatePath = NULL
LOG: DynamicBase = NULL
LOG: CacheBase = NULL
LOG: AppName = MSBuild.exe
Aufruf von Assembly : Microsoft.Build.Tasks.Core, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a.
===

See DisplayName = System.Xml.Linq ...

For Where-Ref binds, there's no DisplayName. That's why Fusion++ sorts them out.

=== Zustandsinformationen vor Bindung ===
LOG: Where-ref-Bindung. Speicherort = D:\Develop\GitHub\msbuild\artifacts\bin\bootstrap\net472\MSBuild\Microsoft\Microsoft.NET.Build.Extensions\tools\net472\Microsoft.NET.Build.Extensions.Tasks.dll
LOG: Appbase = file:///D:/Develop/GitHub/msbuild/artifacts/bin/bootstrap/net472/MSBuild/Current/Bin/
LOG: Ursprünglicher PrivatePath = NULL
LOG: DynamicBase = NULL
LOG: CacheBase = NULL
LOG: AppName = MSBuild.exe
Aufruf von Assembly : (Unknown).
===

What would you say could be the DisplayName for Where-Ref bindings?

[awaescher]

What do you think about this?

for

[KirillOsenkov]

This is perfect! Thanks so much!

[awaescher]

Version 1.4 was just released 🎉

Thank you for the feedback, Kirill.

[Eruvisu]

Can someone tell me what "Where-ref bindings" are? Or where can I find some information about it?
I searched a bit on the internet but I wasn't able to find anything.
I have an issue with one dll where it searches for it in the probing paths and it doesn't find it but then it finds it using 'where-ref'.
And then for the same dll in another application it doesn't use where-ref. It just searches for it in the probing paths and it doesn't find it and that's it.
I used Fusion++ v1.4.

[KirillOsenkov]

Maybe @davkean knows?

[davkean]

WhereRef binds are situations where the assembly name hasn't been set; think Assembly.LoadFrom("foo.dll").

[Eruvisu]

Thanks @davkean for the explanation.

[abelbraaksma]

WhereRef binds are situations where the assembly name hasn't been set; think Assembly.LoadFrom("foo.dll").

Indeed. There are four load contexts (load, load-from, reflection-only, no context). But both LoadFrom and Load(Byte[]) do not provide a name and, unless they were already loaded from a known location previously, they will end up in the load-from context (for found filenames) or no context (for byte arrays). The latter is also true for on-the-fly user-generated assemblies.

Some more info is hidden under the Remarks section here: https://docs.microsoft.com/en-us/dotnet/api/system.reflection.assembly.loadfrom?view=net-6.0#system-reflection-assembly-loadfrom(system-string).